Each year over a million people in the U.S. have a heart attack, also known as a myocardial infarction. About half of them die as a result. Many people have permanent heart damage or die because they don't get help immediately. The symptoms of a heart attack include chest discomfort such as pressure, squeezing, or pain; shortness of breath; discomfort in the upper body including the arms, shoulders, neck, and back; nausea; vomiting; dizziness; lightheadedness; and sweating. Most heart attacks happen when a clot in the coronary artery blocks the supply of blood and oxygen to the heart. Often this leads to an irregular heartbeat, called an arrhythmia, that causes a severe decrease in the pumping function of the heart. A blockage that is not treated within a few hours causes the affected heart muscle to die.
Acute myocardial infarction (AMI) is the death or necrosis of myocardial cells, caused by the interruption of the blood supply to the heart. Much of the damage associated with AMI is due to contraction band necrosis. However, it is now recognized that both apoptosis and necrosis contribute to the myocardial damage seen in patients with AMI with apoptosis contributing to up to 50% of the overall injury. In patients who die after AMI, apoptosis is present in both regions adjacent to and remote from the infarction. Further, while timely reperfusion of the ischemic myocardium can limit infarct size, reperfusion itself may cause damage to the previously ischemic myocardium, including augmentation of the apoptosis which occurs during occlusion. The number of apoptotic cells in the perinecrotic myocardium progressively increases during reperfusion, contributing substantially to the overall extent of the infarction.
Cardiac biomarkers have revolutionized the care of cardiovascular patients in numerous arenas, including prediction and detection of pre-clinical disease, improved detection of cardiac injury including non-ST-segment-elevation myocardial infarction (NSTEMI), prognostication in both acute and chronic disease presentations, and monitoring the response to treatment. Most biomarkers, however, are markers of necrosis. There remains a need for new biomarkers, specifically a biomarker that can detect and quantify apoptosis, suitable detecting and/or diagnosing acute myocardial infarction.